Grinding machine



May 7, 1935- E. G. RQEHM 2,000,614 I GRINDING MACHINE l Filed Nov. 22, 19:53 .5 sheets-sheet 1 fl/ u Sme/rm May 7, 1935. E. s. ROEHM l GRINDING MACHINE Filed Nov. 22, '1935 5 Sheets-Sheet 2 .NNMI

gmc/YM May 7, 1935. E. G'. ROEHM 2,000,614

GRINDING MACHINE Filed Nov. 22, `19253 5 SheeliS-Sl'lee'lI 5 :55 jg`- ZZ] 20j,-

zzz /za/ YW 1%/ lig@ 3 um /A if f///a +5 a 237.5 @3M E l L @htm/MW May 7, 1935. E. G. RoEHM GRINDING MACHINE Filed Nov. 22, 1933 5 Sheets-Shea@ 5 lPatented .May 7, 1935 UNITED STATES;

PATENT oFFlCE Y aoco/614 GRINDING MACHINE Application November 22,1933-, Serial No. 699,203

17 Claims.

'I'his invention relates to improvements. in machine tools and particularly to improvements.

in grinding machines.

One of the principal objects of the present invention is the provision of a new and improved spindle oscillating mechanism as employed with grinding machines.

Another object of the invention is the provision of a spindle reciprocating mechanism of the hydraulically actuated type in which the stroke of the reciprocator may be varied and accurately maintained.

A further object of the invention is the provision of a spindle reciprocating mechanism in which the rate of travel. of the reciprocator may be varied; in which the rate of reciprocation of the spindle vmay be varied in each direction and in which the reciprocation'may take place at a variable slow rate in one direction and a rapid rate in the reverse direction.

A further object of the invention is the provision of an improved spindle reciprocating mechanism in which the spindle may be reversed without forcibly engaging a positive stop, thereby preventing jars and vibrations Ito the machine; in which a dwell is provided at Aeach end of the reciprocatory stroke, andin which .the said dwell may be varied in duration before effecting its reverse reciprocation.

A still further object of the invention is the provision of a spindle reciprocating mechanism which is adapted to be universally adjustable for thereby controlling all of the functions performed by a spindle reciprocating mechanism.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming apart thereof and it is to be understood that any modications may be made in the exact structural details there shown and described, within the scope of the appended claims, Without departing from -or exceeding the spirit of the invention.

In the drawings:

Figure 1 is a front elevational view of a grinding lmachineemhodying the improvements of 'this invention.

Figure 2 is a. top plan view of the machine shown in Figure 1.

Figure 3 is a longitudinal fragmentary sectional view through the grinding wheel spindle taken substantially on line 3-.3 of Figure 1.

Figure 4 is a fragmentary sectional view taken on the same line as Figure 3, but co-ntinuing from where",k Figure 3 stops and particularly 'illustrating the reciprocating mechanism.

Figure 5 is a sectional vview taken on line 5-*5 of Figure-4.

Figure 6 is a sectional view taken on line S-S of Figure 4.

Figure 7 is a. fragmentary sectional view taken on line '1 -1 of Figure 4.

Figure 8 is a sectional view taken on I-B ofl Figure 5.

Figure 9v is a sectional view taken on line line ' 9 9 of Figure 5.

Figure 10 is a view taken substantially on line III-I0 of Figure 1.

Figure 11 is a view partly in section and partly Vin elevation taken on line IIf-II of Figure 10.

Figure 12 is a sectional view takenl on line I2-I2 of Figure 10.

Figure 13 is a diagrammatic view showing the hydraulic circuits involved in the invention.

Throughout the several Views of the drawings similar reference characters are employed to denote the same or similar pieces.

As was noted above, this invention pertains primarily to improved means foreffecting the axial reciprocation of a spindle and the like, particularly grinding wheel spindles, whereby a relative motion is had between the wheel and* work to break up grinding lineson the work. The invention is illustrated in the drawings as employed with a centerless grinder, but it is to be understood that it is not limited to this type of machine, but has application with center type grinders, as well as other types of machine tools in which it is desired to have relative tool and work movements.

The grinding machine shown in the drawings comprises a bed I5 having rising thereabove at one end thereof a pedestal bearing housing IB in which is journaled a spindle II. The bed I5 is further provided on its upper surface with a guide I8 which extends from the grinding wheel bearing to the end of the' bed. The

guide I8 is received in a corresponding guideway formed in the under surface of the slide I9, in turn providing a guide 20 on its upper surface for a second or upper slide 2I. The upper slide 2| has secured thereto a head 22 in which is journaled a spindle 23 for aregulating wheel 24. The regulating Wheel 24 is opposed to 'a grinding wheel 25 secured in any desirable manner to the spindle I'I and the said wheels are spaced from one another to provide a grinding throat 26 in which is located the work 21.

The whee.1 head 22 of the regulating wheel supports on the upper surface thereof a trueing mechanism 28 wherebythe face of the wheel 24 is maintained in a true accurate condition for proper engagement with the work. The grinding wheel 25 is enclosed within a hood or guide 29 which confines the coolant usual with grinding trueing mechanism 3|. The trueing mechanism 3| is adapted to be actuated relative to the wheel for maintaining the face thereof in a .true and sharp condition. In practice the grinding wheel 25 is rotated at a high rate of speed in a clockwise direction, while the regulating wheel 24 is rotated at a relatively slow, work controlling rate of speed also in a clockwise direction. By this construction the proximate portions of the said wheels which form the grinding throat 26 travel in an opposite direction.

The work is supported in the grinding throat by a work rest blade 32 which peripherally engages the work during the grinding operation. The blade 32 is mounted in a block 33 secured, in any desirable manner, to the 'inner end of the primary or lower slide I9.

In order4 to vary the width of the grinding throat 26 the slides I9 and 2| are adapted to be shifted relative to one another and'to the bed I5. For this purpose the upper slide 2| has secured therein a nut 34 in threaded engagement with an adjusting screw 35 journaled in a housing 36 for rotative and axial movement relative thereto. The screw 35 projects beyond the housing 36 to receive a pilot or hand wheel 31 whereby the said screw 35 is rotated; its axial movement being obtained by means to be subsequently described and enclosed within housing 36. In order to move the slide I9 it is clamped to the upper slide 2| by means of the clamp 38, while to eiect the independent movement of the slide 2| relative to the slide I9 the clamp 38 is opened to free the'slides from one another and a clamp 39 is fastened to secure the lower slide. I9 to the bed I5. In practice and to eil'ect a relative feed between the work and grinding wheel the slides I9 and 2| are moved as a unit through the mechanism within the housing 36.

The mechanism within the housing 36 is illustrated in detail in Figures 10, 11 and 12, and as there shown comprises a slide block 40 secured to the screw 35 in such a manner that the screw has rotative movement relative thereto, but is axially shiftable therewith. The block 40 is mounted in a bearing 4I provided bythe housing`36 and the said block has pivotally connected to opposite sides thereof one end of links 42 having their other ends pivotally secured to an l arm 43 projecting from a bell crank lever 44.

. fromf the the cam is l-followed by a second concentric The lever 44 is pivotally connected at 45 and 46 to a web 48 and one wall of the housing 44. The' second arm 49 of the bell crank carries a roller.50 adjustable relative thereto, which roller 5lis received in a cam slot 5I formed in one face of a cam plate 52. The cam slot 5I is provided with a portion 53 for rapidly shifting the slides and work toward the grinding wheel, which portion is followed by a portion 54 for gradually feeding the work into the grinding wheel to effect a stock removal from the work at the desired rate. The portion 54 terminates in a concentric portion 55 and effects a dwell in the feed of the work and wheel and permits a sparking out between the wheel and work whereupon cam portion 56 rapidly retracts the work grinding wheel. This portion 56 of portion 51 which holds the slides in a retracted position to permit a replacement of the work.

In order to rotate the cam 52 it is secured lin any desirable manner to a cam shaft 58 rotatably journaled in a bearing -59 extending from the web 48 or a wall of the housing 36. The shaft 58 projects beyond the bearing 59 to receive a worm wheel 60 in mesh with a worm 6I integral with or secured to a worm shaft as a chain or belt 63 extending yin turn about a small pulley or pinion 64 secured to the shaft 65 of a motor or prime mover 66 carried by the undersurface of the housing 36.

From the foregoing it will now be seen that the Wheels 24 and 25 may be adjusted relative to one another to provide a grinding throat and that the work is automatically fed toward and from the grinding wheel. It is desired during the said grinding operation to effect the axial reciprocation of the grinding wheel and work. It is also desired to initiate the operation of this spindle and wheel reciprocating mechanism at the commencement of the grinding operation and to stop the said reciprocation upon retraction of the Work from the wheel, which operation is effected by the means now to be described.

The cam shaft 58 is projected beyond the rear wall of the housing 36 and has keyed or otherwise secured to said projection 66' a second cam 61 having formed in one face thereof a cam track 68 shown in elevation and, therefore, most clearly in Figure l2. The cam track 68 is provided with two concentric portions 69 and 10 connected at opposite ends by cam portions indicated by the portion 10 will be in a second position. These positions of the valve represent respectivelyl the operation of the spindle reciprocator and the -stopping thereof, and the cam track 68 bears a definite relation to the cam track 5I. Therefore, the spindle reciprocator will be set in motion at the time the work first contacts with the grinding wheel and will be stopped upon retraction of the' work from the grinding wheel. I

The mechanism operable by the cam track 68 includes an arm 13 pivotally connected at 14 to a lug 15 secured in any 'desirable manner to the rear of the housing or casing 36. Intermediate its ends the arm 13 carries a roller 16 disposed withinvthe cam track 68 and at its upper end the arm 13 has a pin and slot connection 11 with the stem 18 of a valve 19. The valve 19 is of the sliding type and has formed thereon a pair of piston portions and 8| forming between them a cannelure 82. The

' cannelure 82 is adapted in one'position of adjustment to connect ports 83 and 84, and in the second position of adjustment to connect ports 83 and 85.

'Ihe ports 83, 84 and 85 are plural in number and extend radially through a valve bushing 86 which encloses the valve 19. The valve bushing 86 is pressed into a valve casing 81 secured in any desirable manner to the rear wall of the housing 36. The valve casing 86, arm 13 and cam 61 are all enclosed within a. suitable guard 88 secured to the rear wall of the housing 36. The valve 19 is 'shown in its operative position in Figure 12, where the spindle reciprocator is operating to effect axial reciproi spindle I1 is provided with a tapered nose 9| on which is pressed and` keyed a grinding wheel coll'et 92 providing the seat for the grinding wheel 25. A clamping plate 93 is secured to the collet 92 for clamping the wheel between itself and the wheel seat formed on the collet 92. Intermediate the bearings 89 and 90 the spindle I1 has keyed or otherwise secured thereto a pulley or slieave 94 sho'tvn in the drawings as a sheave of the multiple V type about which is trained the multiple V belts 95. It is understood that the V belts 9.5,; are in turn trained about a .suitable drivingr source from which the spindle derives its rotative power.

The spindle |1 at its rear end has projecting therefrom a hollow boss 96 receiving a bushing 91 which is provided on opposite sides with a keyway 98. Extending through suitable bores in the boss 96 are keys 99 which enter the key- Ways in the bushing 91. A collar |00 is clamped against the face of the boss 96 by means of a nut I 0|. For holding the bushing 91 within the bore in the boss 96 the bushing 91 is internally threaded and screwed on the inner end of a rod |02' which terminates Within the boss 96. Also disposed Within the boss 96 is a spring |03 abutting on one end with the bushing 91 and on the other end with the base of the bore of the boss and exerts its force against the bushing 91 to take up all backlash and the like between the threads of the said bushing and the rod |02.

The rod |02, see Figure 4, at its other end terminates in a wrench head |04 and collar |05. Seated against the end of the collar |05 is a ring |06 having projecting therefrom a key or keys |01 disposed within a correspondingly shaped keyway formed in the end of a hollow shaft or sleeve |08. The hollow shaft or sleeve |08 encircles the rod |02 and is clamped between the collar |00 and the ring |06 wherefore it is substantially integral with the spindle I1 to partake of all movement imparted to the spring. The rod |02 and sleeve |08 form the connection between the spindle reciprocator and the spindle itself whereby the movement of the reciprocator is imparted to the spindle.

As shown in Figure 4 the hollow shaft or sleeve |08 has secured to it intermediate its ends, as by the nut |09, the inner race ||0 of a double anti-friction thrust bearing. The outer race I l of this bearing is secured to the interior of an hydraulically actuated piston formed of two parts ||2 and ||3, the latter part forming the piston proper and carrying the piston rings.

The piston ||2-||3 is adapted to be recipro cated by hydraulic pressure through a cylinder ||4 which is closed at. one end by a head ||5 including a suitable stufling box and packing. The other end of the cylinder ||4 -is likewise closed by a cylinder head |6 which also includes a packing or stumng box. The cylinder ||4 is secured through a radial ange ||1 to a bracket member ||8, in turn secured to a cylindrical flange or extension ||9 of the pedestal bearing |6. From this it will be' seen` that'thespindle reciprocating mechanism is completely enclosed within a housing secured to the pedestal bearing I6 at the end of the spindle. 'Ihe hydraulic mechanism for effecting the "op-` eration of the piston ||2-'||3 is' shown most clearly in Figure 13 to which reference is now had. As shown therein, there is provided a sump or tank |20 'containing'the hydraulic medium, preferably oil, which is to be circulated through the system for effecting the operationv of the piston. Disposed above the tank |20 is ay pump |2| and extending from one side thereof the suction conduit or pipe |22 which terminates in the "tank |20. Extending from the other side yof the pump is a pressure pipe or conduit `|23 terminating in a, piston reverse valve indicated generally by the numeral |24. The valve |24 is adapted to be actuated by pressure directed to opposite ends thereof by a pilot valve indicated generally by the numeral |25 in -Figure 13. The pilot valve |25 in turn is reversed or reversely operated by pressure under the control of a reversing valve adapted to be positively actuated and indicated in general by the numeral |26, as seen in Figure 13. These valves |24, |25, and |26 are structurally illustrated in Figures 5, 8 and 9, and as there shown, comprise a single valve block |21 secured in any desirable manner` to the bracket ||3 above the spindle bearing housing I6. The positively actuated valve |26, as shown in Figure 8, comprises a valve bushing |28 pressed into a bore |29 formed in the valve block |21. The bushing |28 is provided with a plurality of sets of radial portsy |30, |3I, |32, |33, |34, |35 and |36, each set of which is encircled by a similar groove |31 formed circumferentially of the bushing |28. Disposed within the bore and movable relative thereto is a spool type valve |38 having piston portions |39, |40 and |4I, forming between them cannelures |42 and |43 which connect in different combinations the several sets of radial ports.

Integral with the valve |38 is a stern |44 having formed in outer end, see Figure 4, a notch |45 receiving the ball end |46 of a valve shifter finger |41. The finger |41 is pinned or otherwise secured toa shaft |43 mounted for rocking or oscillating movement in bearings provided by the cylinder head The shaft |48 crosses a notch Qr lway I 49'formed in the said cylinder head ||6 at which point the shaft has secured thereto an arm |50, the free end |5| of which is mounted in a space |52 provided between a ange |53 and a nut |54. The flange |53 is integral with a sleeve nut |55 on which the nut |54 is threaded; the sleeve nut |55 being in turn threaded on the extension sleeve |56 integral with and extending from the piston IIS. From this -it will be seen that the space |52 may be varied for varying the stroke of the `piston since as the ilange |53 and nut |54 are the ends of the valve and are respectively con-' nected, see Figure 13, with drain conduits |51 and |58 which empty into a conduit |59 that terminates in the sump or tank |20. The portsy |33 have connected with them one end of apressure conduit |60 which at its other end connects with the pressure conduit |23. 'I'he ports |32 connect with one end of a pipe orl conduit |6| which terminates at one end of the valve |25 while the ports |34 connect with one end of aport or conduit |62 that terminates at the other end of the said pilot valveV 25. The ports |3| and |35 respectively connect with branch discharge conduits |63 and |64`emptying into conduits |65, |66 and |61, the latter of which terminates in the sump or tank 20.

As was above noted, the pilot valve |25 is adapted to be pressure actuated for which purpose the conduits |6| and |62 are provided for conveying the pressure from the conduit |60 to the opposite ends thereof. This valve 25 is shown most clearly in Figure 9 and comprises a valvebushing |68 which is pressed into a bore |69 in the valve block |21. The bushing |68 is provided with a plurality of sets of radial ports |10, |1|, |12, |13, |14, |15 and |16, each set of ports being encircled by a similar circumferential groove |11 formed in the exterior of the bushing |68. Disposed within the bore in thevalve bushing |68 is a valve |18 adapted to be shuttled relative thereto between adjustable stops |19 and |80. The stops |19 and |80 are identical in construction and each includes a threaded stem |8| threaded into a bonnet |82 in turn threaded in the ends of the bore |69 in the valve block |21.

The shuttle valve |18 is of the spool type having formed near opposite ends thereof piston portions .|83 and |84,.from opposite sides of which project slightly reduced portions |85 and |86. The portions |85 and |86 respectively cooperate with ports 1| and |15 to provide hydraulic resistances and these portions |85 and |86 will therefore be termed resistance portions. Between the piston portions |83 and |84 the valve |18 is provided with collars-|81 and |88 which are spaced from the wall of the bore through the valve bushing to provide hydraulic resistance to the flow of the hydraulic uid therethrough. Between the piston portions |83 and |84 and the collars |81 and |88 are provided cannelures |89, and |9| which effect connection between the radial ports in the bushing in different combinations; and the purpose for the several hydraulic resistances will be explained in full later.-

It is with the ports |10 that the'conduit |6| terminates while the conduit |62 terminates in the ports |16 from which it will be seen that the pressure in the said ports is connected to the opposite ends of the shuttle reversing valve |18. The ports 1| have connected therewith one end of a conduit |92- which terminates at its other end in the ports 84 of the starting and stopping valve 19. The ports |12 and |14 have respectively connected therewith one termini of ports or conduits |93 and |94 which respectively terminate at their other ends in similar independently adjustable choke valves |95 and |96. Connected with the ports |13 is one end of the conduit |66, which as above noted, connects with the conduit |61 emptying into the tank or sump |20. The ports |15 have connected therewith one end of a conduit |91 which terminates at its other end in the piston reversing valve |24.

The piston reversing valve |24 is shown structurally in 1ligure 8 and comprises a valve bushing |98 pressed into a bore in the block |21 and conveniently disposed adjacent the valve 25.

The valve bushing |98 has formed therethrough a plurality of sets of radial ports |99, 200, 20|, 202, 203, 204 and 205, each set being encircled by a similar circumferential groove 206 formed in the exterior of the bushing |98. The bushing is closed at opposite ends by means-of plugs 201 and 208 which limit the travel of a valve relative to the bore of the bushing. The said valve 209 is of the shuttling type and pressure actuated between the said stop plugs 201 and 208. The valve 209 is provided with piston portions 2|0, 2|| and'2l2 adapted to connect in different combinations the several sets 'of radial ports by forming between them cannelures 2|3 and 2|4. It is with the ports 202 that the pressure conduit |23 from the pump connects, while the ports 20| and 203 on opposite sides of the ports 202 respectively connect with one end of conduits 2|5 and 2|6 which respectively' terminate at ports in the right and left hand ends of the piston cylinder ||4, as seen-in Figure 13. The ports 200 and 204 respectively connect through conduits or ports 2|1 and 2|8 with the adjustable valves |96 and |95 and therefore with the conduits |94 and |93 extending from said valves. The port |99 is at the other terminal of the conduit .|91 from the valve |25, as above described, while the ports 205 connect with one end of a pipe or conduit 2| 9 which terminates at its other end in the port 83 of the valve 19.

The remaining port of the valve 19 is connected by a pipe or conduit 220 with the main return conduit |61.

The adjustable throttle valves and |96 are shown structurally in Figure 5, and since they are identical in construction it is deemed sulcient if but one of them be described in detail. Therefore, and as seen in Figure 5, the throttle valve |96 comprises a stem 22| having a knob 222 at one end thereof and a valve portion 223 at its other end. The valve portion 223 is adapted to co-operate with a valve seat 224 formed between the conduit or port |94. From this itl will be seen that the amount of ow between the ports 2|1 and |94 will depend upon the relative positioning or cooperation between the valve 223 and the seat 224.

The operation of this mechanism is as follows:

The grinding wheel spindle is rst rotated through the V belts 95 to effect the rotation of the grinding wheel. It is also assumed, in the case of a centerless grinder, that the regulating wheel is likewise rotated at its proper speed. The infeed mechanism motor 66 is then started for operating the mechanism contained within or associated with the housing 36. This, of course, eiects the rotation of the worm shaft 62 and worm 6| 4for rotating through the worm 60'the cam shaft 58 and the cams 52'and 61 thereon. The cam 52 substantially immediately shifts the work supporting carriages into position for effecting the engagement of the work with the grinding wheel to effect a stock removal from the work.

Substantially at this point the cam 61,

through the arm 13, shifts the valve 19 to the position shown in Figures l2 and 13, 'thereby connecting the conduits |92 and 2|9 or completing the hydraulic circuit whereupon the spindle reciprocating mechanism is operated. The flow of pressure at this time will be through the conduits |23 and |60 to the valve |26 for 2|1 and the throttle valve |96.

. 2,000,614:v vconnecting through theports |33 and I32-the pressure 'with the conduit |6|. The pressure in this conduit is connectedthrough the valve |25 and its ports |10 and |1| with the conduit |92 and therefore the conduit 2|9. This pressure then actson the right hand end of the shuttling piston reversing valve 209 for shifting it to the position shown in Figure 13. When this valve reaches the position shown it connects the ports 202 and 203 so that the pressure in the conduit` |23 then enters the conduit 2|6 and acts on the right hand'end of the spindle reciprocating piston, thereby shifting the said piston, spindle and its grinding wheel to the left or across the work. The hydraulic medium on the other side of the piston is at this time exhausted through the conduit 2|5, ports 20| and 200 of the valve |24 to the port or conduit The valve |96 isadjusted to determine the rate of escape of the hydraulic medium and therefore 4to determine the rate of flow lof the medium and consequently the rate of movement of the piston, spindle and grinding wheel. After the medium passes the throttling valve |96 it flows through th`e`=conduit |94 to the'pilot valve |25 whose ports |14 and |13 connect the medium with conduits |66 andV |61 to the tank |20. l

This movement of vthe spindle, grinding wheel and piston continues to the left until the nut |54, which is moving with the piston, engages.

the valve ,shifter arm |50 for oscillating the shaft |48 and valve shifter |41 to change the position 'of -the valve |26. In other words, through the mechanism above described the valve vmember |38 is shifted to a position for connecting through its cannelure |43 the ports' |33 and |34 -and therefore connecting the branch pressure conduit |60 with the conduit |62. At this timev the pressure in the conduit |62 acts on the left hand end of the shuttling pilot valve member |18 for shifting same to i the right and connect ports |16 and |15 to permit the flow of the medium into the conduit |91. The shifting of the pilot valve member |18 to the right will place the hydraulic resistance collar 81 thereon between the ports |14 and |13, thereby setting up a resistance to the flow of the hydraulic medium through the conduit |94 from the exhaust side of the spindle reciprocating piston. It will be appreciated that the piston is near the end of its stroke when the valve mechanism |26 is actuated,7 but the piston is not quite to the end of its stroke; therefore by throttling this exhaust near the end of its stroke a cushicning action is had Which absolutely prevents a forcible bumping of the piston against a positive stop, in this case the positive 'stop being provided by the nut |54 and cylinder head ||6. It will,

therefore, be seen that the spindle is reversed at one end of its stroke before it actually contacts with the positive stop.

Simultaneously with the action just described the piston reversing valve mechanism |24 is being operated by the'iluid passing througli'the conduit |91. This fluid acting on the left hand` end of the I `,ton memberv 209 shifts same toward the right, as se nin Figure 13, substantially immediately shutting oir the iiow of the pressure through the pressure conduit |23 and thel port 202, thereby stopping the actuating force for shift- -ing the spindle and parts associated therewith.

The movement of 'the valve member 209 effects the discharge of the medium at the other end n 5 thereof, previously utilized for shifting the valve to the position it'now occupies. ed medium is through the ports 205, conduit "2| 9, ports 83 and 84 of the valve mechanism 19,

and 'conduit |92 to the valve mechanism |25. At this time the hydraulic resistance collar is more or less overlying the ports |1| to more or less restrict the flow of fluid therethrough, depending upon the adjustment of the stop |19. This, as above described, sets up an hydraulic resistance which slows up or tends to delay the actual shifting of the valve member 209, thereby causing `a delay in the movement of the spindle and parts associated therewith at one end of their stroke. This delay may be regulated or varied by varying the position of the stop |19, thereby changing the hydraulic resistance or 'throttling action on the ow of the fluid through the conduit |92 and port 1|. It is to be understood that the stop |19 may be adjusted to a position to maintain the ports |1| uncovered, thereby offering no resistance to the ow of fluid therethrough and permitting a rapid or substantially ins tantaneous shifting of the valve member 200. From this it will be seenthat the rate of shifting of the valve member 209 may be adjusted for effecting a' variable delay at one end of the reversal of the spindle and parts associated therewith. J y

The valve 209 is nally shifted to engage its other stop 201, thereby connecting the ports 202 and 20| for directing the hydraulic medium in the conduit |23 against the left hand end of the spindle reciprocating piston for shifting the parts to the right, as seen in Figure 13.

This movement of the spindle and parts as' 'valve mechanism is actuated for shifting its |38 to the position shown in At this time the pressure valve member Figures 8 and 13;

then acts through the conduit |6| on the right l hand end of the shuttlingpilot valve for shifting same to the position sliiwn in the drawings. Depending upon the adjustment of adjustable stop |80 the hydraulic resistance collar |06 takes a position with respect to the ports |15 for controlling the 110W therethrough.

With the pilot valve member |18 in its'left hand position the hydraulic pressure is down through the conduits |92 and 2|9 to the right hand end of the piston reversing valve member 209 for shifting same to the left. The movement of the valve member 209 to the left exhausts the medium ahead of it through the conduit |91, 'ports |15 and conduit |62 .where it is connected through the valve mechanism |26 with the discharging conduits |65, |66 and |61. The movement of the piston reversing valve member 209-is delayed and controlled, however, by the hydraulic resistance collar |86 in the same manner as the reverse movement thereof was controlled as above described. From this it will be seen that a delay may be provided at each end of the spindle stroke and that said delay may be varied or adjusted by merely varying the adjusting stops |19 and |80.

When the valve reaches the position shown in Figure 13 'the spindle and the parts associated therewith are actuated to the left, this move- This exhaustment being controlled by the throttle valve n as described above. By the present conversing valve is broken, the spindle and grinding wheel will always stop at the same end of i its stroke. This will be appreciated when it is remembered that upon shifting of the valve 19 v by the cam 61 the conduit or pipe 2| 9 is connected with the pipe or conduit 220 and the sump, while upon reversal of the valve mechanism |26, as by the spindle, no flow of pressure will be had to the valve mechanism |24.

'From the foregoing it is believed now evident that there has been provided a spindle reciprocating mechanism in which the movement of the spindle, and therefore the grinding wheel, may be independently controlled and independently varied in each direction so that a rate of speed in each direction may be provided, depending upon the nature and type of the work. It'will also be noted that there may be provided a variable delay at each end of the spindle stroke, which variable delay may be independ-A ently varied or adjusted depending upon the desires of the operator. It will further be noted that the spindle is prevented from forcibly engaging a positive stop at each end of its stroke, yet the said limits of the reciprocatory stroke may be very accurately determined and maintained. Y

In order to vary the length of stroke of the spindle without in any wise changing or varying the adjustment above or without interfering with the said adjustments it is only necessary to adjust the nut |54 on the sleeve nut |55 and to adjust the flange |53 of the sleeve |55 on the extension |56 of the piston What is claimed is,

1. In a spindle reciprocating mechanism of the class described the combination of a housing having bearings formed therein, a spindle mounted in said bearings for rotation and axial movement relative thereto, means for effecting said axial reciprocation of the spindle, means for varying the rate of said reciprocation, and means for eecting a dwell at each end of said reciprocation.

2. In a spindle reciprocating mechanism of the class described the combination of a housing having bearings formed therein, a spindle mounted in said bearings for rotation and axial movement relative thereto, means for effecting said axial reciprocation of the spindle, means for varying the rate of said reciprocation, means for effecting a dwell at each end of said reciprocation, and means for varying the duration of said dwell.

3. A spindle reciprocating mechanism of the class described including in combination with a housing having mounted therein a spindle for rotative and axial movement relative thereto, of a piston and cylinder mechanism secured to said spindle for reciprocating same, an hydraulic'circuit for actuating the piston and consequently the spindle, and independently adjustable means at each end of the reciprocatory stroke for limiting the movement of the piston in each direction.

4. A spindle reciprocating mechanism of the class described including incombination with a housing having mounted rtherein a spindle for rotative and axial movement relative thereto, of a piston and cylinder mechanism secured to said spindle for reciprocating same, an hydraulic circuit for actuating the piston and consequently the spindle, adjustable means for limiting the movement of the piston in'each direction, a valve in said circuit for reversing the ow therethrough toA reverse the operation of the spindle, and means between the valve and piston movement limiting means whereby the said valve is operated.

` 5. A spindle reciprocating mechanism of the class described including in combination with a housing having mounted therein a spindle for rotative and axial movement relative thereto, of a piston and cylinder mechanism secured to said spindle for. reciprocating same, an hydraulic circuit for actuating the piston and consequently the spindle, adjustable. means for limiting the movement of the piston in each direction, a valve in said circuit for reversing the flow therethrough to reverse the operation of the spindle, means between the valve and piston movement limiting means whereby the said valve is operated, and a valve in said circuit for initiating and stopping the flow through the circuit.

6. In a spindlereciprocating mechanism of the class described the combination with a spindle supported for axial sliding movement within its bearings, of a piston secured to the spindle,-

an hydraulic circuit for reversely axially actuating the piston and consequently the spindle, a starting and stopping valve in said circuit, a pressure actuated reversing valve for alternately directing the pressure to opposite ends of the piston, and independently adjustable means for controlling the flow of the fluid from ea'ch end of 'said piston for thereby adjustably varying the rate of movement of the piston in each direction.

'7. In a spindle reciprocating mechanism of the class described the combination of a piston secured to the spindle, an hydraulic circuit for reversely axially actuating the piston and consequently the spindle, a starting and stopping valve in said circuit, a pressure actuated reversing valve for alternately directing the pressure to opposite ends of the piston, independently adjustable means for controlling the flow of the fluid from each end of said piston for thereby adjustably varying the rate of movement of the piston in each direction, and means for delaying the operation of the pressure actuated reversing valve to provide a tarry in the movement of the piston.

8. In a spindle reciprocating mechanism of the class described'the combination of a piston secured to the spindle, an hydraulic circuit for reversely axially actuating the piston and consequently the spindle, a starting and stopping valve in said circuit, a pressure actuated reversing valve for alternately directing the pressure to opposite ends of the piston, independently adjustable means for controlling the flow of the fluid from each end of said piston for thereby adjustably varying. the rate of movement of the piston in each direction, and adjustableI means for delaying the operation of the piston reversing valve whereby a variable delayl at each end of the piston stroke is provided.

9. In a spindle reciprocating mechanism of the class described the combination of a piston secured to the spindle, an hydraulic circuit for reversely axially actuating the piston and consequently the spindle, a-starting and stopping valve in said circuit, a pressure actuated reversing valve for alternately directing the pressure to opposite ends of 'the piston, independently adjustable' means for controlling the flow of the fluid from each end of said piston for thereby adjustably varying the rate of movement of the piston in each direction, adjustable means for delaying the operation of the piston reversing valve whereby a variable delay at each end of the piston stroke is provided, and means for slowing down the movement of the piston at each end of its stroke to eliminate a forcible engagement between the piston and its stop.

l0. In a spindle reciprocating mechanism of the class described the combination of a piston secured to the spindle, an hydraulic circuit for reversely axially actuating the piston and consequently the spindle, a starting and stopping valve in said circuit, a pressure actuated reversing valve for alternately directing the pressure to opposite ends of the piston, independently adjustable means for controlling the flow of the fluid from each end of said piston for thereby adjustably varying the rate of movement of the piston in each direction, adjustable means for delaying the operation of the piston reversing valve whereby a variable delay at each end of the piston stroke is provided, said means comprising an adjustable hydraulic resistance which limits the exhaust from the pressure operated piston reversingvalve, and means for varying the effectiveness of said resistances.

11. In a spindle reciprocating mechanism of the class described the combination with bearings, and a spindle mounted therein for reciprocation relative thereto, of an hydraulically actuated piston secured to said spindle, an hydraulic circuit for actuating the piston, a starting and stopping valve in the circuit for initiating and stopping the movement of the piston, a reversing valve for alternately connecting the pressure side of the circuit with the ends of the piston, independent and adjustable means for controlling the exhaust fiow from the piston to vary the rate of travel of` the piston in each direction, independently adjustable means for delaying the operation of the reversing valve whereby to' effect an adjustable delay lin the movement of the piston at each end of its stroke, and means operable just prior to each end of the piston stroke for cushioning same and slowing down its movement for thereby eliminating jars and the like incident to the reversal of the piston.

12. In a spindle reciprocating mechanism of the class described4 the combination with bearings, and a spindle mounted therein for reciprocation relative thereto, of an hydraulically actuated piston secured to said spindle, an hydraulic circuit for actuating the piston, a starting and stopping valve in the circuit for initiating and stopping the movementof the piston, a reversing valve for alternately connecting the pressure side of the circuit with the ends of the piston, independent and adjustable-means for controlling the exhaust flow from the piston to vary the rate of travel of the piston in each direction, independently adjustable means for delaying the operation of the reversing valve whereby to eiect an adjustable delay in the ciprocation of a grinding wheel spindle or the like with respect to its bearings including a piston member directly associated with the spindle for positively eifecting back and forth movements thereof, hydraulic mechanism for effecting said movements of the piston, a control' valve, lost motion mechanical connections between the control valve and the piston for effecting intermittent actuations of the valve from movements of the piston, and an hydraulic actuating system including serially arranged valve mechanisms controlled by the mechanical connection with the first mentioned valve for determining the operative effect of the piston.

14. A mechanism for effecting a limited reciprocation of a grinding wheel spindle or the like with respect to its bearings including a piston member directly associated with the spindle for positively effecting back and forth movements thereof, hydraulic mechanism for effectl5. A mechanism for eifecting a limited reciprocation of a grinding wheel spindle or the like with respect `to its bearings including a piston member directly associated with the spindle for positively effecting back and forth movements thereof, hydraulic mechanism for effecting said movements of the piston, a control valve, lost motion mechanical connections between the control valve and the piston for effecting' intermittentv actuations of the valvefrom movements of the piston, an hydraulic actuating system including serially arranged valve mechanisms controlled by the mechanical connection with the first mentioned valve for determining the operative eiect of the piston, and

additional manually adjustable means for vary- Y ing the lost motion connection between the piston mechanism and the valve actuating member for varying the period between reversals effective through the hydraulic system.

16. A mechanism for effecting a limited reciprocation of a grinding wheel spindle or the like with respect to its bearings including a piston member directly associated with the spindle for positively effecting back and forth -movements thereof, hydraulic mechanism for effecting said movements of the piston, a control valve, lost motion mechanical connections between the control valve and the piston for effecting intermittent actuations of the valve from movements of the piston, an hydraulic actuating system including serially arranged valve mechanisms controlled by the mechanical connection with thefirst mentioned vvalve for determining the operative effect ofthe piston, said hydraulic system including a power transmitting conduit, and additional valve means operable to interrupt the fiow through said conduit.

17. A mechanism for effecting a limited re ciprocation of a grinding wheel spindlefor the `like with respect to its bearings including a piston member directly associated with the spindle for positively effecting back and forth movements thereof, hydraulic mechanism for eilecting said movements of the piston, a control valve, lost motion mechanical connections be- 5 tween the control valve and the piston for effecting intermittent actuations of the valve from movements otvthe piston, an hydraulic actuating system includin'g serially arranged valve mechanisms controlled by the mechanical con- Asnoooinfa,

- nection with the rst mentioned valve for demine the several positionings of said last men-4 tioned valve.

`ERWIN G. RQEHM. 

